Read the next record from that batch, and return it as a MARC::Record object. If the current file is at EOF, close it and open the next one. next() will return undef when there is no more data to be read from any batch files.

By default, next() also will return undef if an error is encountered while reading from the batch. If not checked for this can cause your iteration to terminate prematurely. To alter this behavior, see strict_off(). You can retrieve warning messages using the warnings() method.

Optionally you can pass in a filter function as a subroutine reference if you are only interested in particular fields from the record. This can boost performance.

The opposite of strict_off(), and the default state. You shouldn't have to use this method unless you've previously used strict_off(), and want it back on again. When strict is ON calls to next() will return undef when an error is encountered while reading MARC data. strict_on() always returns true (1).